A cave on the island of Timor has given archaeologists a significant clue to the route taken by historic people after they first made their strategy to the Australian continent.

It’s identified from archaeological proof in Australia’s Northern Territory that individuals have been there a minimum of 65,000 years in the past. At the moment, when sea ranges have been decrease, Australia and New Guinea have been half of a bigger landmass generally known as Sahul.

Researchers imagine there are two possible routes folks may have taken from South-East Asia to Sahul. One is a southern route by way of Timor. Alternatively, Homo sapiens may have travelled by way of Sulawesi, an island to the north of Timor.

Now, Sue O’Connor on the Australian Nationwide College in Canberra and her colleagues imagine they’ve discovered proof ruling out the likelihood that the primary arrivals got here by way of Timor.

In different places on Timor, the oldest proof of human occupation was lower than 50,000 years outdated. Archaeologists have been unable to search for older artefacts as, in any respect the opposite websites they studied, they hit bedrock somewhat than sediment layers that might doubtlessly comprise proof of an earlier presence, says O’Connor.

In 2019, her crew dug a brand new pit at a cave known as Laili, on the north coast of East Timor, and found a wealthy deposit of archaeological proof together with tens of hundreds of stone instruments, proving that people had occupied the island for 44,000 years.

Crucially, nonetheless, this layer of occupation was underlain by sediments with no proof of people. This implies it’s possible that earlier than 44,000 years in the past, folks have been absent, says O’Connor.

“That is the primary time in Timor that we have now sterile, non-occupation layers beneath proof of individuals’s presence,” she says.

O’Connor says such a transparent boundary between no proof of people adopted by tens of hundreds of years of artefacts is named an “arrival signature”.

The cave’s distinguished location and entry to assets offers the researchers confidence that it’s unlikely to have been missed by any early people travelling by way of the realm.

“It’s a very, actually large cave with an enormous flowing river in a braided floodplain and really near the coast,” says O’Connor. “It’s an ideal place for folks to determine an occupation base camp. You couldn’t discover a extra superb setting.”

Due to the proof that individuals have been in Australia 65,000 years in the past however not in Timor till 44,000 years in the past, it means people almost certainly migrated by way of the islands to the north, says O’Connor.

“Trying on the layers in Laili cave, it’s like ‘bang’ – you’ll be able to actually see clearly when the folks arrive,” she says. “It was like a line had been drawn between the 2 layers – earlier than folks and after folks. It was so clear.”